Ahmed A Shabana

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Deformable components in multibody systems are subject to kinematic constraints that represent mechanical joints and specified motion trajectories. These constraints can, in general, be described using a set of nonlinear algebraic equations that depend on the system generalized coordinates and time. When the kinematic constraints are augmented to the(More)
The serum levels of tissue polypeptide-specific (TPS) antigen were measured using the M3 monoclonal antibody in an enzyme immunoassay in 33 patients with ovarian cancer, in 26 women with benign pelvic masses and in 26 women with a laparoscopically proven normal pelvis. The results were compared with the serum levels of the CA 125 antigen. At a cutoff level(More)
The dynamic simulation of multibody tracked vehicles offers engineers a powerful tool with which they may analyze and design. Currently, parts of these complex mechanisms are introduced to multibody algorithms as rigid bodies. Then in a follow-on structural analysis, the loads from the multibody dynamic simulation are input to calculate strains and stresses(More)
In order to determine the best approach for the modeling of tracked vehicle-terrain interactions, a comparison is made between terramechanics and continuum mechanics plasticity soil models that can be used in vehicle dynamic simulations. The absolute nodal coordinate formulation (ANCF) which can be used in multibody system (MBS) dynamics to model large(More)
The levels of the soluble forms of the membrane-bound receptor for tumor necrosis factor (TNF), p55 and p75, were assessed in peritoneal fluid samples from 50 patients with ovarian cancer, from 20 patients operated for benign pelvic masses, and from 26 healthy women undergoing laparoscopy. The 95% cutoff for normal levels were 14.0 and 5.2 ng/ml for p55 and(More)
Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this(More)
Multibody system (MBS) computer codes currently being used are based on three-decade old technology that is failing to respond to new modeling challenges. Modern and complex ground vehicle models, for example, include significant details that cannot be captured using existing MBS software technology. This paper discusses a new Department of Defense (DoD)(More)
To describe a modified surgical approach in the form of stepwise cesarean section in placenta percreta. We conducted a prospective observational study. A total of 71 patients with placenta percreta were subjected to the new stepwise surgical approach and uterine repair at the time of cesarean delivery. The procedure was successful in controlling the(More)